Figure 4
CCL19 gradients induce DC chemotaxis in a microfluidic migration chamber.
(a) DCs migrating in a diffusion based gradient of cell culture medium (R10). (b–d) DCs migrating in a diffusion based CCL19/FITC dextran 10 kDa gradient. (e) Directionalities as a function of the position in the microfluidic assay for low (left panel) intermediate (middle panel) and high (right panel) average concentrations of CCL19. The zero position corresponds to the lower edge of the field of view in (b–d), where the respective concentration is maximal. The directionalities are shown for short, intermediate, and long times, shown in blue, green, and red. The concentration range covered during each period of time is indicated in the respective colour. (b) and (e). 1) Lower third of the migration chamber; low CCL19 concentration regime. (c) and (e). 2) Middle third of the migration chamber; medium CCL19 concentration regime. (d) and (e). 3) Upper third of the migration chamber; high CCL19 concentration regime. Left panel: Representative images of the CCL19/FITC dextran 10 kDa and the cell culture media (R10) gradient at t = 60 min. Middle panel: Corresponding cell track analysis of all tracks aligned to the origin [dimensions in μm; time is colour-coded]. Gradient direction and pattern shape are indicated in grey. Right panel: Rose plot visualizing the distribution of angles of all tracks in an angular sector field with tracks split into 3 min intervals.
